The present invention relates generally to automatic locking retractors for automotive seat belts and more particularly to anti-cinch devices included with such retractors for permitting a certain amount of free play in the operation of the retractor during normal use.
While the prior art is replete with examples of so-called automatic locking retractors, that is, seat belt retractors which are effective to prevent substantial further extension of the seat belt webbing after the belts are donned by the wearer, the prior art automotive locking retractors typically have one operational limitation which, in certain circumstances, can make their use inconvenient or uncomfortable. This is the "cinching" effect encountered when the belt is retracted during use to a tighter position. This can occur during slight movement of the wearer in the seat of a vehicle, particularly compressing movement against soft seat cushions. Automatic locking retractors typically have relatively sensitive locking mechanisms which permit protracting or extending movement of the belt to take place while the belt is being donned and which provide for locking the belt against further protraction after the belt is retracted to a comfortable position with respect to the wearer's body. Such locking may be effected by pawl and ratchet type mechanisms in which a pawl lockingly engages with a ratchet tooth during protracting movement once the lock is effected. In these retractors, the retracting movement of the belt is always permitted and is in fact urged by a return spring in a webbing take-up reel of the mechanism. When shifting movement of the occupant, as against a soft seat cushion, occurs in the direction which will permit such retracting movement while the belt is being worn, the possibility exists that the pawl and ratchet mechanism may be repositioned to a new tighter position as a result of the unplanned retracting movement.